Guide wire with multiple polymer jackets over distal and intermediate core sections

ABSTRACT

The invention is directed to a guide wire having at least two different polymeric jackets that impart different handling characteristics to the portions of the guide wire they surround. Preferably, the guide wire may have jackets of different grades of polymer, such as polyurethane 55 D and 90 A. Alternatively, the guide wire may have jackets of different types of polymers such as polyurethane and polytetrafluoroethylene, or may have a single polymeric jacket with continuously varying properties along its length. The invention also comprises methods of making such guide wires.

BACKGROUND OF THE INVENTION

This invention relates to the field of guide wires for advancingintraluminal devices such as stent delivery catheters, balloondilatation catheters, atherectomy catheters and the like within bodylumens.

In a typical percutaneous procedure, a guiding catheter having apreformed distal tip is percutaneously introduced into a patient'speripheral artery, e.g. femoral or brachial artery, by means of aconventional Seldinger technique and advanced therein until the distaltip of the guiding catheter is seated in the ostium of the desiredcoronary artery. There are two basic techniques for advancing a guidewire into the desired location within the patient's coronary anatomy,the first is a pre-load technique which is used primarily forover-the-wire (OTW) devices and the bare wire technique which is usedprimarily for rail type systems.

With the pre-load technique, a guide wire is positioned within an innerlumen of an OTW device such as a dilatation catheter or stent deliverycatheter with the distal tip of the guide wire just proximal to thedistal tip of the catheter and then both are advanced through theguiding catheter to the distal end thereof. The guide wire is firstadvanced out of the distal end of the guiding catheter into thepatient's coronary vasculature until the distal end of the guide wirecrosses the arterial location where the interventional procedure is tobe performed, e.g. a lesion to be dilated or a dilated region where astent is to be deployed. The catheter, which is slidably mounted ontothe guide wire, is advanced out of the guiding catheter into thepatient's coronary anatomy by sliding over the previously introducedguide wire until the operative portion of the intravascular device, e.g.the balloon of a dilatation or a stent delivery catheter, is properlypositioned across the arterial location. Once the catheter is inposition with the operative means located within the desired arteriallocation, the interventional procedure is performed.

With the bare wire technique, the guide wire is first advanced by itselfthrough the guiding catheter until the distal tip of the guide wireextends beyond the arterial location where the procedure is to beperformed. Then a rail type catheter, such as described in U.S. Pat. No.5,061,395 (Yock) and the previously discussed McInnes et al. which areincorporated herein by reference, is mounted onto the proximal portionof the guide wire which extends out of the proximal end of the guidingcatheter which is outside of the patient. The catheter is advanced overthe guide wire, while the position of the guide wire is fixed, until theoperative means on the rail type catheter is disposed within thearterial location where the procedure is to be performed. After theprocedure the intravascular device may be withdrawn from the patientover the guide wire or the guide wire repositioned within the coronaryanatomy for an additional procedure.

Further details of guide wires, and devices associated therewith forvarious interventional procedures can be found in U.S. Pat. No.4,748,986 (Morrison et al.); U.S. Pat. No. 4,538,622 (Samson et al.):U.S. Pat. No. 5,135,503 (Abrams); U.S. Pat. No. 5,341,818 (Abrams etal.); and U.S. Pat. No. 5,345,945 (Hodgson, et al.) which are herebyincorporated herein in their entirety by reference thereto.

Conventional guide wires for angioplasty, stent delivery, atherectomyand other vascular procedures usually comprise an elongate core memberwith one or more tapered sections near the distal end thereof and aflexible body member such as a helical coil or a tubular body ofpolymeric material disposed about the distal portion of the core member.A shapeable member, which may be the distal extremity of the core memberor a separate shapeable ribbon which is secured to the distal extremityof the core member extends through the flexible body and is secured tothe distal end of the flexible body by soldering, brazing or weldingwhich forms a rounded distal tip. Torquing means are provided on theproximal end of the core member to rotate, and thereby steer, the guidewire while it is being advanced through a patient's vascular system.

A problem confronting designers of successful guide wires is thedesirability to provide different physical characteristics for differentparts of the guide wire. For example, many guide wires have a highlyflexible leading tip designed not to damage or perforate the vessel.Further, the portion behind the distal tip is increasingly stiff tobetter support a balloon catheter or similar device. The more proximalportion of the guide wire must also have sufficient torsional rigidityto allow the tip to be steered through the coronary vasculature.

One solution that has been employed is to provide a guide wire having acore member with tapered diameters as discussed above. However, it canbe difficult to obtain the desired handling characteristics on the basisof core wire dimensions alone. Other solutions have involved the use ofdifferent materials for different portions of the guide wire. Theseattempts raise new problems in obtaining appropriately secureconnections between the different materials while maintaining thedesired low profile. Further, it can be important to provide a smoothtransition between regions of different stiffness in a guide wire tominimize the potential of kinking.

It is also desirable to provide a guide wire with a lubricious coatingto facilitate advancement of the guide wire through the tortuouscoronary vasculature. However, placing suitable coatings on metal guidewires raises significant manufacturing problems. Typically, the metalsurface must be pretreated to allow adhesion of the lubricious coating.This adds to the expense and difficulty of producing guide wires. Thepresent invention solves these and other problems.

SUMMARY OF THE INVENTION

This invention is directed to an elongate intraluminal device having anelongate core member with a proximal portion, an intermediate portionand a distal portion with a first polymeric jacket and a secondpolymeric jacket disposed about the core member. In a preferredembodiment, the first polymeric jacket is disposed about theintermediate portion of the elongate core and the second polymericjacket is disposed about the distal portion of the core. Preferably, theintraluminal device is a guidewire and the first polymeric jacket iscomposed of a different polymer than the second polymeric jacket, or thefirst polymeric jacket has different polymeric properties than thesecond polymeric jacket. The use of different polymers or polymerproperties imparts different handling characteristics to the variousportions of the guide wire. Preferably, the first polymeric jacket isharder or has a higher shore hardness than the second polymeric jacketso that the distal portion of the guide wire is more flexible than theintermediate portion.

The polymeric jackets may comprise any suitable polymers such aspolyurethanes or fluoropolymers. In one preferred embodiment, the firstjacket comprises polyurethane having a shore hardness of up to about 70D, preferably about 50 D to about 60 D. The second jacket is generallyis of a softer or more flexible material than the first jacket.Typically a polyurethane having a shore hardness of about 75 A to about100 A, preferably about 85 A to about 95 A is used for the secondjacket. In a typical embodiment, a first jacket of shore hardness 55 Dis used with a second jacket having a durometer of 90 A. While the useof two discrete polymer jackets is preferred, the invention is alsodirected to the use of three or more polymer jackets as well as a singlepolymer jacket having a continuously varying shore hardness over alongitudinal length of the single polymer jacket. In another preferredembodiment, the first jacket is made of polyurethane while the secondjacket is made of a fluoropolymer. In embodiments where the guide wirehas a shapeable coil at the distal tip, the second jacket should coverthe coil.

The invention also includes a processes for making guide wires havingmultiple polymeric jackets or a jacket of continuously varyingcharacteristics to impart differing handling characteristics todifferent portions of the guide wire. Preferably, the process involvesjacketing the guide wire by hot die necking. In embodiments where theguide wire has a shapeable coil over a core member, it may be desirableto configure the process so that gaps between the turns of the coil andbetween the coil and the core member are filled with polymeric materialto minimize any air voids.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a guide wire of the invention having a shapeable coiltip and first and second polymeric jackets.

FIGS. 2 and 3 are cross sections of the guide wire of FIG. 1 showing thefirst and second polymeric jackets.

FIG. 4 shows an alternate embodiment of the invention having differentconfiguration of polymeric jackets.

FIGS. 5 and 6 are cross sections of the guide wire of FIG. 4 showing thefirst and second polymeric jackets.

FIG. 7 is another embodiment of the invention with first and secondpolymeric jackets and without a helical coil distal tip.

FIGS. 8-10 are cross sections of the guide wire of FIG. 7 showing thefirst, second and third polymeric jackets.

FIG. 11 is an elevational view in partial section of a guidewire havingfeatures of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1-3, a guide wire 10 of the present inventiongenerally comprises a proximal core portion 12, an intermediate coreportion 14 and a distal core portion 16. Running through the proximal,intermediate and distal core portions of the guide wire 10 is anelongated core member 18 typically having varying diameters to providedifferent handling characteristics to the different portions of theguide wire. A typical 0.014 inch diameter guide wire to be used incoronary applications will preferably have sections with diameters ofabout 0.014 in., 0.010 to 0.007 in., 0.005 to 0.004 in., and 0.003 to0.002 in. extending from the proximal end to the distal end. However,other diameters are also suitable for the invention depending on theapplication. For example, guide wires used in the peripheral vasculaturewould be correspondingly larger. Generally, elongate core member 18 ofguide wire 10 is stainless steel, but it may also comprise a shapememory material such as nickel-titanium alloys or other materials. Guidewire 10 has a shapeable distal tip 20 that comprises a flexible helicalcoil 22. The distal end has a rounded end 24, preferably formed by asolder plug securing helical coil 22 to core member 18.

As shown in the cross sections FIGS. 2 and 3, polymeric jackets 26 and28 surround intermediate core portion 14 and distal core portion 16,respectively. In this embodiment, the polymeric jackets comprisepolyurethane, with jacket 26 having a shore hardness of about 50 D toabout 60 D and jacket 28 having a shore hardness of about 85 A to about95 A. By selecting different grades of polymer, the intermediate 14 anddistal 16 portions of guide wire 10 can be given different handlingcharacteristics. In some embodiments, it may be preferable to configurethe guide wire so that any spaces between the individual coils of thehelical coil 22 or between the coil 22 and the core member 18 aresubstantially filled by polymeric jacket 28.

FIGS. 4-6 show an alternative embodiment, wherein guide wire 30comprises proximal 32, intermediate 34 and distal 36 core portionsformed from elongated core member 38. Guide wire 30 also has a shapeabledistal tip 40, comprising helical coil 42 secured to core member 38.Cross sections FIGS. 5 and 6 show polymeric jackets 46 and 48surrounding intermediate core portion 34 and distal core portion 36,respectively. In this embodiment, polymeric jacket 46 comprisespolyurethane while jacket 28 comprises a fluoropolymer such aspolytetrafluoroethylene (PTFE). As before, selecting different types ofpolymers for the two jackets imparts different mechanical and handlingcharacteristics to the different regions of the guide wire.

FIGS. 7-10 show yet another embodiment of the invention, wherein guidewire 50 similarly comprises proximal 52, intermediate 54 and distal 56core portions formed from elongated core member 58. However, theshapeable distal tip comprises a shapeable ribbon 60 rather than ahelical coil. FIGS. 8-10 show cross sections of guide wire 50, whereinthe intermediate core portion 54 has polymeric jacket 62, distal coreportion 56 has polymeric jacket 64 and a third polymeric jacket 66bridges the intermediate core portion 54 and the distal core portion 56.As before, the jackets desirably have polymers of different type orgrade so that the intermediate and distal portions of the guide wire maybe designed to have different handling characteristics. The use of athird type of polymer for the third jacket 66 provides greater controlover the handling characteristics of the guide wire.

Further, polymeric jackets 62, 64 and 66 have a lubricious coating 68 tofacilitate travel of the guide wire 50 through a patient's vasculature.A lubricious coating is very easy to apply to polymers and thus thisavoids the difficulties attendant in obtaining adequate adhesion of alubricious coating to the metal of the guide wire. In addition, whilethe materials for polymer jackets 62, 64, and 66 can be chosen formechanical properties, the polymers of the jackets can also be selectedfor surface characteristics. The lubricious, hydrophylic, andhydrophobic characteristics of polymers used for polymer jackets 62, 64,and 66 can be selected to provide optimum performance of the guidewire50.

While polymer jackets 62, 64 and 66 have been described as discrete, itis also possible for the jackets to be blended together at theboundaries therebetween, or for any single jacket member to have avarying composition over its entire length that varies the shorehardness of the jacket over the length. For example, in FIG. 7, ifjackets 62, 64 and 66 are combined into a single jacket member, thatjacket member can have a hardness of about 50 D to about 60 D,preferably about 55 D at a proximal end of the combined jacket and ahardness of about 85 A to about 95 A, preferably about 90 A at a distalend of the combined jacket. The hardness variation from the proximal endof the jacket to the distal end of the jacket could vary in any usefulcontinuous manner including linearly or according to some other desiredfunction. A continuous variation in shore hardness of a polymer jacketcan be achieved by varying the mixture of two polymers having differentshore hardnesses during the extrusion process. Another method forvarying the shore hardness of a single polymer jacket is to radiationtreat the polymer jacket to a varying degree along its longitudinallength. It is known in the art that certain types of gamma or e-beamradiation can alter the shore hardness of certain polymers depending onthe intensity and duration of exposure.

The invention also comprises processes for manufacturing guide wireshaving the features described above. Generally, the process of theinvention includes the steps of providing a guide wire having proximal,intermediate and distal core portions; jacketing the intermediate coreportion with a first polymeric material and jacketing the distal coreportion with a second polymeric material. The polymeric materials shouldbe processed so that they conform closely to the elongated core memberand the shapeable distal tip. Preferably, tubes or sleeves of polymericmaterial are hot die necked onto the guide wire. As an alternative,tubes or sleeves of suitable polymeric material can be heat shrunk overan elongate core member to produce the desired result. In someembodiments, it may be desirable to minimize any air gaps between thehelical coil itself or between the coil and the core member. This may beachieved by heating the die to assure the polymer flows into the coil.Additionally, a lubricious coating may be applied to the surface of atlast a portion of the polymeric jackets. Homopolymers, copolymers,blends, and coextrusions may be used to vary the properties of thepolymers.

As discussed above the polymeric material may be any suitable,biocompatible material including polymers such as polyurethane,fluoropolymers such as polytetrafluoroethylene, PVC, polyimide,polyamide, Nylon PET, PEEK and the like. In one preferred embodiment, aguide wire is jacketed with a first polymeric material comprisingpolyurethane and a second polymeric material comprisingpolytetrafluoroethylene. Where the first and second polymeric materialare the same, different grades or shore hardnesses should be used toimpart different handling characteristics to the different portions ofthe guide wire. For example, in another preferred embodiment, a guidewire is jacketed with a first polymeric material comprising polyurethanehaving a hardness of about 55 D and a second polymeric materialcomprising polyurethane having a hardness of about 90 A. In yet otherembodiments, it may be desirable to provide more than two differentpolymeric jackets in order to impart a greater range of handlingcharacteristics to the guide wire. In addition to shore hardness, othercharacteristics of the polymeric jackets can be varied to produce thedesired performance. For example, the radiopacity of the polymericjackets could be varied by including differing percentages by weight ofradiopaque materials in the polymer material. Suitable radiopaquematerials would include tantalum powder, barium sulfate, bismuth, gold,platinum and the like.

FIG. 11 shows an alternative embodiment of a guidewire 70 havingfeatures of the invention. The guidewire 70 has an elongate core member71 with a proximal core section 72 and a distal core section 73. Thedistal core section has a proximal end 74 and a distal end 75 which ispreferably rounded. The distal core section 73 has a tapered segment 76located at the proximal end 74. A helical coil 77 is disposed about aportion of the distal core section 73. The helical coil 77 is preferablymade from a radiopaque metal such as gold, platinum, tantalum, iridiumor the like, but can also be made out of stainless steel or othersuitable alloys. A first polymer jacket 78 and second polymer jacket 81are disposed about the distal core section 73 and encompass the helicalcoil 77 and any gaps between portions of the helical coil. The firstpolymer jacket 78 and second polymer jacket 81 are joined at lap joint82. The lap joint 82 is angled with respect to a line perpendicular to alongitudinal axis of the elongate core member 71. The angled lap joint82 provides a strong smooth transition between the first polymer jacket78 and second polymer jacket 81. The second polymer jacket 81 has adistal end 83 that is preferably rounded to reduce trauma to the insidesurface of a patient's body passageways in which the guidewire 70 isadvancing.

The distal core section 73 of the elongate core member 71 has asubstantially constant outer diameter over a length thereof. The outerdiameter of the distal section is about 0.002 to about 0.01 inches,preferably about 0.005 to about 0.007 inches. The length of the distalcore section 73 is about 10 to about 60 cm, preferably about 20 to about40 cm. The proximal core section 72 has an outer diameter of about 0.011to about 0.015 inches, preferably about 0.012 to about 0.014 inches. Theelongate core member 71 is made of stainless steel, but could also bemade of pseudoelastic alloys such as NiTi, or high strengthprecipitation hardenable alloys such as MP35N, L605, precipitationhardenable stainless steel or the like. The first polymer jacket 78 ismade from a polyurethane with a shore hardness of about 55 D to about 65D. The second polymer jacket 81 is made from a polyurethane with a shorehardness of about 75 A to about 85 A. As with the previously describedembodiments of the invention, the first and second polymer jackets 78and 81 can be made from a variety of polymer materials includingpolyamides, copolymers, and nylons such as Pebax. Although guidewire 70is shown in FIG. 11 with two polymer jackets, three or more polymerjackets could be used to cover or partially cover the distal coresection 73 of the elongate core member. Also, in addition to multiplepolymer jackets that are softer and more flexible distally along theelongate core member 71, alternative configurations could be usedwhereby an intermediate polymer jacket has a shore hardness less than aproximal polymer jacket located proximally to the intermediate polymerjacket and less than a distal polymer jacket located distal to theintermediate polymer jacket. This would give the guidewire a distalsection with a more flexible intermediate portion.

While particular forms of the invention have been illustrated anddescribed, it will be apparent that various modifications can be madewithout departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited, except asby the appended claims.

What is claimed is:
 1. A guidewire comprising an elongate core memberhaving a proximal portion, an intermediate portion and a distal portionhaving a most distal end, a first polymeric jacket disposed about atleast part of the intermediate portion and a second polymeric jacketformed at least in part of a fluoropolymer disposed about at least partof the most distal end of the distal portion.
 2. The guide wire of claim1 wherein the first and second polymeric jackets have different physicalcharacteristics.
 3. The guide wire of claim 2 wherein the first andsecond polymeric jackets have different shore hardnesses.
 4. The guidewire of claim 2 further comprising at least one additional polymericjacket disposed about the elongate core member and having physicalcharacteristics different from the first and second polymeric jacket. 5.The guide wire of claim 3 wherein the first polymeric jacket comprisespolyurethane having a shore hardness of about 50 D to about 60 D, andthe second polymeric jacket comprises polyurethane having a shorehardness of about 85 A to about 95 A.
 6. The guide wire of claim 3wherein the first polymeric jacket comprises a polyurethane and thesecond polymeric jacket comprises a fluoropolymer.
 7. The guide wire ofclaim 1 wherein a distal portion of the guide wire further comprises ashapeable coil secured to the elongate core member and wherein thesecond polymeric jacket is disposed about the shapeable coil.
 8. Theguide wire of claim 7 wherein shapeable coil has spaces between adjacentcoils and spaces between the shapeable coil and the elongate core memberand wherein the polymeric jacket fills substantially all the spaces. 9.A guidewire comprising an elongate core member having a proximalportion, an intermediate portion and a distal portion having a mostdistal end, and a polymeric jacket disposed about at least part of theintermediate portion and at least part of the most distal end of thedistal portion and having a shore hardness that varies continuouslyalong the longitudinal length of the polymer jacket.
 10. The guide wireof claim 9 wherein the polymer jacket further comprises a proximal endand a distal end and varies linearly in shore hardness from about 55 Dat a proximal end to about 90 A at a distal end.